New research by the University of Southampton has found a mechanism as to how corals use their pink and purple hues as sunscreen to protect them against harmful sunlight.
Many reef corals need light to survive, as they benefit from sugars and lipids that are produced by their light-dependent symbiotic algae. However, in the shallow water of coral reefs, light levels are often higher than required by the corals, so paradoxically, the vital sunlight can become harmful for the algae and their hosts.
Apart from temperature, light stress is a major driver of coral bleaching the loss of the symbiotic algae that represents a threat to coral reef survival.
Working in the Great Barrier Reef and under tightly controlled conditions in the Coral Reef Laboratory of the University of Southampton, the team of researchers produced experimental evidence that the pink and purple chromoproteins can act as sunscreens for the symbiotic algae by removing parts of the light that might become otherwise harmful.
Dr Jrg Wiedenmann, Senior Lecturer of Biological Oceanography and Head of the University's Coral Reef Laboratory, who led the study says: "The beautiful pink and purple hues that are produced by the coral host are often evoked by chromoproteins; pigments that are biochemically related to the green fluorescent protein (GFP) of the jellyfish Aequorea victoria. In contrast to their green glowing counterpart, the chromoproteins take up substantial amounts of light, but they don't re-emit light.
"GFP-like proteins were suggested to contribute to the protection of corals and their symbionts from excess sunlight. This hypothesis has been controversially discussed as the mechanism as to how these pigments function remained unclear. At least for the chromoproteins we know now that they have indeed the capacity to fulfill this function."
The researchers also proposed an explanation for the mysterious phenomenon that some corals accu
|Contact: Glenn Harris|
University of Southampton